The present invention relates to a flame-resisting resin composition. More specifically, the present invention relates to a flame-resisting resin composition exhibiting a high impact resistance.
Among plastics moldings, most of plastics moldings for electrical and electronic parts, for automobile components as well as for use in factories are particularly required to have an excellent flame-resistance of the V-0 grade of the UL Standard. Moreover, many of these moldings are also required to have a good impact resistance.
A number of resins are known as flame-resisting resins. Polyarylene sulfide, for instance, is well-known to exhibit the V-0 grade of the UL Standard. It is, however, difficult to say that moldings made of polyarylene sulfides satisfy the requirement of the impact resistance. It has been proposed, therefore, to incorporate thereinto an impact modifier such as a copolymer of ethylene and a glycidyl ester of an .alpha.,.beta.-unsaturated mono-carboxylic acid. Such resultant resin composition exhibits a flammability of the V-2 grade of the UL Standard or out of the grade of that Standard, and thus fails to satisfy the desired flame-resistance level.
The UL Standard herein used is specified in the "Standard for Tests for Flammability of Plastic Material for Parts in Devices and Appliances", UL 94, Fourth Edition, by Underwriters Laboratories Inc., according to which the "V-0" level is a higher grade in flame-resistance than the "V-2" level, since the V-0 level means a shorter time for which a material continues to flame than that of the V-2 level.
The offer of a rein composition having a flame-resistance of the V-0 grade of the UL Standard and exhibiting a high impact resistance is demanded.
As a result of the present inventors' earnest studies for fulfilling such requirements, it has been found that by adding to a polyarylene sulfide (A) a graft copolymer (B) composed of an olefinic copolymer (a) having 30 to 59% by weight (based on the weight of the graft copolymer) of an .alpha.-olefin repeating unit and a glycidyl ester residue repeating unit of an .alpha.,.beta.-unsaturated mono-carboxylic acid, and polymers (b) having the repeating unit represented by the following formula (I), the olefinic copolymer (a) being branched or crosslinked with one or more of the polymers (b), the obtained resin composition possesses a flame-resistance of the V-0 grade of the UL Standard and exhibits a high impact resistance: ##STR2## (wherein R represents a hydrogen atom or a lower alkyl group having from 1 to about 6 carbon atoms, X represents a benzyl group, --COOCH.sub.3, --COO.sub.2 H.sub.5, --COOC.sub.4 H.sub.9, --COOCH.sub.2 CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9, --CN, a phenyl group or a maleimide group) .
On the basis of the finding, the present invention has been attained.